(1) Field of the Invention
The present invention relates to cigarettes which produce minimal amounts of tar and other harmful organic substances with the heat occurring with smoking, thereby to minimize the harmful effect of smoking on health.
(2) Description of the Prior Art
Cigarettes comprising tobacco rolled in paper (rice paper) are manufactured and distributed in great quantities since they are handy to smoke anywhere without necessitating pipes or other instruments.
However, cigarettes are more harmful than cigars and pipe tobacco, and tend to cause troubles of circulatory organs such as the heart and blood vessels, and diseases such as bronchitis, stomach ulcer, hepatocirrhosis and so on. Cigarette smoking is said to have a high probability of leading to lung cancer in particular. The reason is believed to lie in that cigarettes have a relatively high burning temperature (800.degree. C.) compared with other types of tobacco, which tends to produce tar and other cancerating substances.
The cigarette includes tobacco and paper (rice paper). The paper is formed by combining fibrous base materials such as staple fiber, flax and hemp with various combustion improvers.
If the cigarette is disintegrated into tobacco and paper which are then lit separately, they burn gradually with the paper giving a royal purple smoke having a peculiar irritating smell and tobacco giving a white smoke.
Upon comparison, the smoke from the paper has a far more irritating smell and a far greater irritating effect on mucosae of the nose and eyes than the smoke from tobacco.
When a glass rod at the temperature of 25.degree. C. is exposed to each of these smokes, tar adheres to the glass rod. The color of tar is darker when the glass rod is exposed to the smoke from the paper than when it is exposed to the smoke from the tobacco. Furthermore, this tar contains large amounts of cancerating substances such as benzopyrene and benzantrasen.
Incidentally, there are two types of tobacco smoke. One is a white smoke (or a primary smoke) flowing through the cigarette itself into the smoker's mouth, and the other is a purple smoke (or a secondary smoke) rising from a burning position.
The secondary smoke contains far greater amounts of harmful substances than the primary smoke. Since this smoke is alkaline, it greatly irritates mucosea. The World Health Organization has warned in recent years that non-smokers staying near smokers are risking their health by inhaling the harmful secondary smoke into their lungs, thereby to develop troubles of the respiratory organs, lung cancer, and other diseases.
As a result, the "Non-Smoker's Rights" have been claimed throughout the world.
Cigarettes have been proposed recently, in Japanese Utility Model Application Kokai No. 56-129294, which are rolled in incombustible sheets of paper formed by mixing a paper material with pumice powder and asbestos powder.
These cigarettes are intended for preventing fires caused by smoking in bed, careless handling of cigarette ends remaining alight, and throwing away cigarette ends. This proposal is not made with a view to reducing the hazard to health due to the harmful organic substances produced by the burning paper of cigarettes. The proposal has the following problem also.
Since the incombustible sheet comprises a paper base material over which asbestos powder and the like are distributed, tar and other harmful organic substances are produced when the cigarettes are smoked or left alight with the paper subjected to incomplete combustion. These harmful substances fill a room or inhaled through the mouth, thereby giving rise to the same problem as in the case of other known cigarettes.
Furthermore, the asbestos powder used in the incombustible sheet may cause pseumoconiosis to the detriment of health.